Process for preparing coppercontaining azo dyestuffs



Patented May 14, 1946 PROCESS FOR PREPARING COPPER- CONTAINING AZO DYESTUFFS Norman L. Anderson, Buffalo, N. Y., assignor to Allied Chemical & Dye Corporation, New York, N. Y., a corporation of New York No Drawing. Application November 7, 1942, Serial No. 464,884

9 Claims.

This invention relates to an improved process for preparing copper-containing azo dyestuffs. More particularly the invention relates to an improved process for preparing copper complex derivatives of azo dye compounds by reacting cop pering agents with azo dye compounds of a particular type; namely, those containing at least one radical having the following configuration:

I OH 01130 wherein A and B represent aromatic nuclei.

It was known heretofore to prepare copper complex derivatives of azo dye compounds by heating azo compounds of the aforesaid class with copper salts in aqueous solution. Owing to the fact, however, that the process involves elimination of a methyl group from the methoxy radical of th azo dye compound, the process as heretofore practiced was subject to a number of disadvantages. Thus, as is pointed out by Mendoza-in U. S. P. 2,036,159, earlier processes were generally subject to the disadvantage that the reaction was incomplete, so that coppered dyestufis of relatively inferior dyeing and fastness properties were obtained. To secure complete re-' action in coppering the primary disazo compound obtained by coupling one mol of tetrazotized o-dianisidine with two mols of 1,8 -amino 4. naphthol-2,4-disulfonic acid, Mendoza proposed boiling the disazo compound under reflux with an aqueous ammoniacal copper sulfate solution, until evolution of methylamine had ceased (about hours).

I have found, in accordance with the present invention, that it is possible by means of my improved process to overcome the disadvantages of the said prior procedures, without having to resort to boiling under reflux. Thus, in carrying out the process according to my invention, the coppering treatment may be performed in an open vessel, resulting in considerablesaving in cost and upkeep of equipment.

Further, I have found that, in the case of oertain copper complex derivatives prepared by my improved process, they have superior properties cellulose; whereas the dyestuffs obtained from the same azo dye compounds by boiling under reflux .contain decomposition products (presumably as a result of the higher temperature conditions) which impair the brightness of shade of dyeings produced with the dyestuffs and stain organic derivatives of cellulose. Consequently, in the case of such copper complex derivatives, the coppered dyestuffs produced by my improved method can be advantageously employed for cross-dyeing union fabrics containing organic derivatives of cellulose, such as celluloseacetate fiber, together with cellulosic fiber, such as cotton or regenerated cellulose rayon. i

In preparing copper-containing azo dyestuffs by my improved process, the heating of the azo dye compound of the aforesaid type with an aqueous .ammoniacal solution of a copper salt, preferably of a cupric salt, is carried out at a temperature between and 100 0., and preferably at a temperature of to C., in the presence of metallic copper. I

Metallic copper may be added to the reaction mixture in the form of dust, filings, thin sheets,

or the like, or it is sufficient merely to employ a reaction vessel of metallic copper. While I have not been able to determine conclusively the reason for the beneficial effect of the metallic copper, it seem probable that the metal acts as a catalyst in the reaction, so as to facilitate the formation of the copper complex derivative of the azo dye compound.

, escapes.

Ammoniacal copper sulfate is generally employed as the coppering agent; although other F water-soluble copper salts, especially cupric salts,

which are adapted to form a cupramine complex with ammonia may be employed. The ammonia may be conveniently added in the form of an aqueous solution, e. g., 2'7 to 28% aqua ammonia. The proportions of the reagents are preferably such thatat least one atomic equivalent of copper is present for each azo group equivalent included are preferably employed for each atomic equivalent of bivalent copper in the form of its salts, and generally a moderate excess of ammonia (e. g., 15 to 20% of the theoretical amount required) is maintained in the mixture during the reaction. For this purpose small amounts of am monia may be added to the mixture during the reaction in order to replace any ammonia which The reaction mixture generally com- ,prises suflicientwater to yield a concentration of 7 about one-tenth mol in terms of parts by weight of azo dye compound for each 1000 parts by perature of the mass for 24 hours in a glass vessel weight of water. equipped with a reflux condenser.

The azo dye compound is suspended or dissolved in the water to ether with the copper salt PaTt C and the ammonia. Copper is also added, unless 5 The disazo compound is heated with aqueous the reaction is carried out in a vessel having a ammoniacal copper lf t at s to for 24 copper surface in contact with the reaction mixhours in an Open copper Vesselture. The mixture is heated at temperatures be- The ccpper complex derivatives Obtained f tween 85 and 100 C. and preferably at a temparts A, B and h employed for dyeing cotel'atule of to The temperature is ton, yield blue shades which compare as follows: maintained the reaction is COmPlete. COm- The copper-containing dye tuff of Part C pro.-

p n of t a n generally requires from duces a shade much greener and brighter than bout 24 o about 43 hours- Temperatures of the dyestuff of Part A, and considerably greener 100 C. or more are avoided since ammonia is and brighter t th dyestuff of rt B, The evolved so rapidly at Such temp as 130 dyestufi of Part B produces shades slightly der t e process uneeonomioal. and in some. greener than the dyestuff of Part A, but considercaSeS e pper complex thereby formed becomes ably redder than the dyestuff of Part C, while contaminated with undesirable impurities. At the dyeing produced with the dyestuff of Part A temp at s sub y below 0-, t e is much redder than that from the dyestufi of action is too slow to be of commercial value. t 1 (Degrees of iff rence, in order of in- The invention will be more readily understood greasing difference are; appreciably consjd from the following examples in which parts are erably, much. Samples of cotton dyed with y weight and temp ratures ar in re s t the three dyestuffs, when tested for light fastness grade. by exposure for 48 hours in a Fade-Ometer, yield Ewample Parts Of the diSaZO ye eo results indicating the dyestufis of Parts B and C p d obtai ed by uplin one m f t az to be substantially equally fast, While the dyetized o-diaIflSidine With two mole o Sodium stuff of Part A is considerably inferior to those benzoylamino-8-naphtho12,4disulfonate in alof Parts B and C.

kaline solution are agitated with 1000 parts of These results clearly show the superiority of water. The suspension is heated to 90 to 95 30 dyestuffs produced by my improved process as and 5 parts of copper filings are added. An compared with similar dyestufis produced by the aqueous solution of 25 parts of copper sulfate reflux method, or by heating at less than reflux (CuSOI-l2O) and 30 parts of aqua ammonia temperature in the absence of metallic copper.

(27% NH3) in 100 parts of water is added and Example 3.-A disazo dye compound is prothe reaction mixture is a itated for about 48 duced by tetrazotizing o-dianisidine and coupling hours in an open vessel while maintaining the with R salt in the following manner: 19.6 parts temperature at 90 to 95. Small amounts of of o-dianisidine are mixed with 320 parts of waammonia are added from time to time during the ter containing 16.1 parts of 22 B. hydrochloric reaction to replace the ammonia which escapes. acid. The mixture is heated to and then The reaction mixture is filtered to separate the cooled by addition of 300 parts of ice. 26 parts of copper filings, and 200 parts of sodium chloride 22 B. hydrochloric acid and 11.4 parts of sodium are added to the filtrate. Upon cooling to about nitrite are then added, and the mixture is agi- 20 the dyestufi is precipitated, filtered from the tatecl for two hours. The solution of tetrazo mother-liquor, and recovered in the form of a o-dianisidine thus formed is added rapidly to an filter cake. Upon drying the latter, a copperice-cold aqueous solution made up of 49.2 parts containing dyestuff is obtained having the folof monosodium 2-naphthol-3,6-disulfonate, 64 lowing probable formula: parts of sodium carbonate, 400 parts of ice and Example 2.-Three equal portions of the disazo 480 parts of water. The temperature is maincompound employed in Example 1 (obtained by tained at 0 to 5 by further addition of ice, and coupling one mol of tetrazotized o-dianisidine the coupling reaction is permitted to continue for with two mols of sodium 1-benzoy1amino-8- about 16 hours. At the end of this period, the naphthol-2,4-disulfonate in alkaline solution) are mixture is heated to and sodium chloride is converted into the corresponding copper complex added in an amount equivalent to 20% of the derivative by heating with equal amounts of weight of a volume of Water equal to that of the aqueous ammoniacal copper sulfate of the same 55 reaction mixture. The mixture is then'cooled composition in the following manner: to about 20, and the resulting disazo compound Part A thereby precipitated isrecovered by filtration in the form of a filter cake. The latter is divided The a o C p is heated With the q into two equal portions which are treated as folous ammoniacal copper sulfate at to for 70 lows: 24 hours in an open glass vessel. Part A Part B One portion is mixed with 800 parts of water, The disazo compound is heated with the aqueand to the mixture is added a solution made up ous ammoniacal copper sulfate at the boiling tomof 24 parts of copper sulfate (CuSOa5H2O), 28

' separated by water. The mixture is heated to boiling temperature andboiled under reflux for 24 hours.

The mixture is then salted with sodium chloride,

and cooled to precipitate the copper complex of the azo dyestufip The precipitatedproduct is filtration, and the filter cake is Part B dried.

compound ,is suspended, in 800 parts .of water, and to the mixture is added a solution made up of 24 parts of copper sulfate (CuSO4.5I-IaO), 28

parts of aqua ammonia (27%), and 80 parts of water, together with 'parts of copper filings. The mixture is then heated in an open vessel for 24 hours at 90 to 95. After filtering out the copper filings, the copper complex of the dyestuff is separated by salting out, and recovered in the manner above described.

The copper-containing dyestuifs thus, obtained dye cotton in substantially the same reddish-blue shades Their probable formula is as follows:

The improved process of this invention may be similarly applied with advantage to other azo dye compounds containing at least one radical having the configuration as defined above.

For instance, instead of the disazo dye compounds of the foregoing examples, there may be substituted an equivalent quantity of a disazo compound having the following probable formula:

NE, on 011,0, 00H. on soon more N=N-C N=N N80] NaOaS NaOgS Variations and modifications may be made in the details of the foregoing examples without departing from the invention. Accordingly, the foregoing details are not to be interpreted in a limiting sense.

' Certain of the 'copper containing dyestuffs disclosed above are claimed in m application'Serial No. 464,885, filed of even date herewith, and my application Serial No. 486,702, filed May 12, 1943.

I claim: 1. In a process for preparing copper complex derivatives of azo'dye compounds by reacting an aqueous ammoniacal solution of a copper salt 7 V Q :with an azo dye compound containing at least The. other portion of the filter cake of the azo one radicalhaving the following configuration:

reaction "in an aqueous ammoniacal solution of a copper salt, in the presence of metallic copper,

at a temperature between and C.

2. In a process for preparing copper complex derivatives of azo dye compounds by reacting an aqueous ammoniacal solution of a copper salt with anazo dye compound containing at least one radical having the following configuration:

wherein A and B represent aromatic,nuclei, the

improvement which comprises carrying out said reaction in an aqueous ammoniacal solution of a cupric salt, in the presence of metallic copper, at a temperature between 85 and 100 C.

3. In a process for preparing copper complex derivatives of azo dye compounds by reacting a coppering agent with an azo dye compound containing at least one radical having the following configuration:

wherein A and B represent aromatic nuclei, the improvement which comprises heating said azo dye compound in an aqueous ammoniacal solution of a cupric salt containing at least suflicient copper to provide one atomic equivalent thereof for each equivalent of said radical, and at least 4 molecular equivalents of ammonia per atomic equivalent of copper at a temperature between 0 SOsNB 85 and 100 C. in the presence of metallic copper.

4. In a process for preparing copper complex derivatives of azo dye compounds by reacting a coppering agent with an azo dye compound containing at least one radical having the following OH CHaO wherein A and B represent aromatic nuclei, the improvement which comprises heating said azo dye. Co pound in an aqueous ammoniacal solution of a cupric salt containing at least sufficient copper to provide one atomic equivalent thereof for each equivalent of said radical, and at least 4 molecular equivalents of ammonia per atomic equivalent of copper, at a temperature of 90 to 95 C. in the presence of metallic copper until the copperin reaction is substantially complete. 5. A -process of preparing a copper-containing azo dyestuff, which comprises heating a disazo compound containing a radical having the 'following configuration:

, A?N=N B --13' N=N A B 01130 00133 HO comprises heating a symmetrical disazo com- 1 pound obtainable by coupling one mol of tetrazotized o-dianisidine with two mols of a l-benzoylamino-8-naphthol-2,4-disulfonate, with an aqueous ammoniacal solution of a cupric salt containing at least sufiicient copper to provide 2- atomic equivalents thereof for each molecular equivalent of said disazo compound, and at least equivalent of copper, at a temperature of 90 to 95" C. in-the presence of metallic copper, for a period of about 24 to about 48 hours.

7. A process for preparing a copper-containing azo dyestuif for dyeing cellulosic materials, which comprises heating a symmetrical disazo compound obtainable by coupling one mol of tetrazotized o-dianisidine withtwo mols of a 2-naphthol-3,6-disulfonate, with an aqueous ammoniacal solution of a cupric salt containing at least sufficient copper to provide 2 atomic equivalents thereof for each molecular equivalent of said disazo compound, and at least 4 molecular equivalents of ammonia per atomic equivalent of copper, at a temperature of 90 to 95 C. in the presence of metallic copper, for a period of about 24 to about 48 hours.

8. A process for preparing a copper-containing azo dyestuff for dyeing cellulosic materials, which comprises heating a disazo compound obtainable by coupling one mol of tetrazotized o-dianisidine with one mol of a 1-amino-8-naphthol-2,4-disulfonate on the one hand, and with one mol of a 1-naphthol-3,8-disulfonate on the other hand,

' with an aqueous ammoniacal solution of a cupric salt containing at least suffioient copper to provide 2 atomic equivalents thereof for each molecular equivalent of said disazo compound, and at least 4 molecular equivalents of ammonia per atomic equivalent of copper, at a temperature of '90 to C. in the presence of metallic copper,

for a period of about 24 to about 48 hours.

9. A copper-containing azo dyestuif obtained by heating a disazo compound obtainable by coupling one mol of tetrazotized o-dianisidine with two mols of a 1-benzoylamino-8-naphthol-2,4- disulfonate, with an ammoniacal solution of a cupric salt at a temperature between 85 and C. in the presence of metallic copper, and salting out the resulting dyestuif.

NORMAN L. ANDERSON. 

